SSE2 implementation of RGBA box blurs. This yields ~2X perf improvement on Xeon ES-2690.

R=mtklein@google.com

Review URL: https://codereview.chromium.org/61643011

git-svn-id: http://skia.googlecode.com/svn/trunk/src@12204 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/effects/SkBlurImageFilter.cpp b/effects/SkBlurImageFilter.cpp
index c04c258..852c0af 100644
--- a/effects/SkBlurImageFilter.cpp
+++ b/effects/SkBlurImageFilter.cpp
@@ -10,6 +10,7 @@
 #include "SkColorPriv.h"
 #include "SkFlattenableBuffers.h"
 #include "SkGpuBlurUtils.h"
+#include "SkBlurImage_opts.h"
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #include "SkImageFilterUtils.h"
@@ -125,26 +126,6 @@
     }
 }
 
-static void boxBlurX(const SkPMColor* src, int srcStride, SkPMColor* dst, int kernelSize,
-                     int leftOffset, int rightOffset, int width, int height)
-{
-    boxBlur<kX, kX>(src, srcStride, dst, kernelSize, leftOffset, rightOffset, width, height);
-}
-
-#ifndef SK_DISABLE_BLUR_DIVISION_OPTIMIZATION
-static void boxBlurXY(const SkPMColor* src, int srcStride, SkPMColor* dst, int kernelSize,
-                              int leftOffset, int rightOffset, int width, int height)
-{
-    boxBlur<kX, kY>(src, srcStride, dst, kernelSize, leftOffset, rightOffset, width, height);
-}
-#endif
-
-static void boxBlurY(const SkPMColor* src, int srcStride, SkPMColor* dst, int kernelSize,
-                     int topOffset, int bottomOffset, int width, int height)
-{
-    boxBlur<kY, kY>(src, srcStride, dst, kernelSize, topOffset, bottomOffset, width, height);
-}
-
 static void getBox3Params(SkScalar s, int *kernelSize, int* kernelSize3, int *lowOffset,
                           int *highOffset)
 {
@@ -212,6 +193,13 @@
     SkPMColor* d = dst->getAddr32(0, 0);
     int w = dstBounds.width(), h = dstBounds.height();
     int sw = src.rowBytesAsPixels();
+    SkBoxBlurProc boxBlurX, boxBlurY, boxBlurXY;
+    if (!SkBoxBlurGetPlatformProcs(&boxBlurX, &boxBlurY, &boxBlurXY)) {
+        boxBlurX = boxBlur<kX, kX>;
+        boxBlurY = boxBlur<kY, kY>;
+        boxBlurXY = boxBlur<kX, kY>;
+    }
+
     if (kernelSizeX > 0 && kernelSizeY > 0) {
 #ifndef SK_DISABLE_BLUR_DIVISION_OPTIMIZATION
         boxBlurX(s,  sw, t, kernelSizeX,  lowOffsetX,  highOffsetX, w, h);
diff --git a/opts/SkBlurImage_opts.h b/opts/SkBlurImage_opts.h
new file mode 100644
index 0000000..a8fb209
--- /dev/null
+++ b/opts/SkBlurImage_opts.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkBlurImage_opts_DEFINED
+#define SkBlurImage_opts_DEFINED
+
+#include "SkColorPriv.h"
+
+typedef void (*SkBoxBlurProc)(const SkPMColor* src, int srcStride, SkPMColor* dst, int kernelSize,
+                              int leftOffset, int rightOffset, int width, int height);
+
+bool SkBoxBlurGetPlatformProcs(SkBoxBlurProc* boxBlurX,
+                               SkBoxBlurProc* boxBlurY,
+                               SkBoxBlurProc* boxBlurXY);
+#endif
diff --git a/opts/SkBlurImage_opts_SSE2.cpp b/opts/SkBlurImage_opts_SSE2.cpp
new file mode 100644
index 0000000..97cd2fd
--- /dev/null
+++ b/opts/SkBlurImage_opts_SSE2.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#include "SkBitmap.h"
+#include "SkColorPriv.h"
+#include "SkBlurImage_opts_SSE2.h"
+#include "SkRect.h"
+
+#include <emmintrin.h>
+
+namespace {
+
+enum BlurDirection {
+    kX, kY
+};
+
+/**
+ * Helper function to spread the components of a 32-bit integer into the
+ * lower 8 bits of each 32-bit element of an SSE register.
+ */
+
+inline __m128i expand(int a) {
+      const __m128i zero = _mm_setzero_si128();
+
+      // 0 0 0 0   0 0 0 0   0 0 0 0   A R G B
+      __m128i result = _mm_cvtsi32_si128(a);
+
+      // 0 0 0 0   0 0 0 0   0 A 0 R   0 G 0 B
+      result = _mm_unpacklo_epi8(result, zero);
+
+      // 0 0 0 A   0 0 0 R   0 0 0 G   0 0 0 B
+      return _mm_unpacklo_epi16(result, zero);
+}
+
+template<BlurDirection srcDirection, BlurDirection dstDirection>
+void SkBoxBlur_SSE2(const SkPMColor* src, int srcStride, SkPMColor* dst, int kernelSize,
+                    int leftOffset, int rightOffset, int width, int height)
+{
+    const int rightBorder = SkMin32(rightOffset + 1, width);
+    const int srcStrideX = srcDirection == kX ? 1 : srcStride;
+    const int dstStrideX = dstDirection == kX ? 1 : height;
+    const int srcStrideY = srcDirection == kX ? srcStride : 1;
+    const int dstStrideY = dstDirection == kX ? width : 1;
+    const __m128i scale = _mm_set1_epi32((1 << 24) / kernelSize);
+    const __m128i half = _mm_set1_epi32(1 << 23);
+    const __m128i zero = _mm_setzero_si128();
+    for (int y = 0; y < height; ++y) {
+        __m128i sum = zero;
+        const SkPMColor* p = src;
+        for (int i = 0; i < rightBorder; ++i) {
+            sum = _mm_add_epi32(sum, expand(*p));
+            p += srcStrideX;
+        }
+
+        const SkPMColor* sptr = src;
+        SkColor* dptr = dst;
+        for (int x = 0; x < width; ++x) {
+#if 0
+            // In SSE4.1, this would be
+            __m128i result = _mm_mullo_epi32(sum, scale);
+#else
+            // But SSE2 has no PMULLUD, so we must do AG and RB separately.
+            __m128i tmp1 = _mm_mul_epu32(sum, scale);
+            __m128i tmp2 = _mm_mul_epu32(_mm_srli_si128(sum, 4),
+                                         _mm_srli_si128(scale, 4));
+            __m128i result = _mm_unpacklo_epi32(_mm_shuffle_epi32(tmp1, _MM_SHUFFLE(0,0,2,0)),
+                                                _mm_shuffle_epi32(tmp2, _MM_SHUFFLE(0,0,2,0)));
+#endif
+            // sumA*scale+.5 sumB*scale+.5 sumG*scale+.5 sumB*scale+.5
+            result = _mm_add_epi32(result, half);
+
+            // 0 0 0 A   0 0 0 R   0 0 0 G   0 0 0 B
+            result = _mm_srli_epi32(result, 24);
+
+            // 0 0 0 0   0 0 0 0   0 A 0 R   0 G 0 B
+            result = _mm_packs_epi32(result, zero);
+
+            // 0 0 0 0   0 0 0 0   0 0 0 0   A R G B
+            result = _mm_packus_epi16(result, zero);
+            *dptr = _mm_cvtsi128_si32(result);
+            if (x >= leftOffset) {
+                SkColor l = *(sptr - leftOffset * srcStrideX);
+                sum = _mm_sub_epi32(sum, expand(l));
+            }
+            if (x + rightOffset + 1 < width) {
+                SkColor r = *(sptr + (rightOffset + 1) * srcStrideX);
+                sum = _mm_add_epi32(sum, expand(r));
+            }
+            sptr += srcStrideX;
+            if (srcDirection == kY) {
+                _mm_prefetch(reinterpret_cast<const char*>(sptr + (rightOffset + 1) * srcStrideX),
+                             _MM_HINT_T0);
+            }
+            dptr += dstStrideX;
+        }
+        src += srcStrideY;
+        dst += dstStrideY;
+    }
+}
+
+} // namespace
+
+bool SkBoxBlurGetPlatformProcs_SSE2(SkBoxBlurProc* boxBlurX,
+                                    SkBoxBlurProc* boxBlurY,
+                                    SkBoxBlurProc* boxBlurXY) {
+    *boxBlurX = SkBoxBlur_SSE2<kX, kX>;
+    *boxBlurY = SkBoxBlur_SSE2<kY, kY>;
+    *boxBlurXY = SkBoxBlur_SSE2<kX, kY>;
+    return true;
+}
diff --git a/opts/SkBlurImage_opts_SSE2.h b/opts/SkBlurImage_opts_SSE2.h
new file mode 100644
index 0000000..4dd804a
--- /dev/null
+++ b/opts/SkBlurImage_opts_SSE2.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBlurImage_opts.h"
+
+bool SkBoxBlurGetPlatformProcs_SSE2(SkBoxBlurProc* boxBlurX,
+                                    SkBoxBlurProc* boxBlurY,
+                                    SkBoxBlurProc* boxBlurXY);
diff --git a/opts/SkBlurImage_opts_none.cpp b/opts/SkBlurImage_opts_none.cpp
new file mode 100644
index 0000000..dbdac8a
--- /dev/null
+++ b/opts/SkBlurImage_opts_none.cpp
@@ -0,0 +1,14 @@
+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBlurImage_opts.h"
+
+bool SkBoxBlurGetPlatformProcs(SkBoxBlurProc* boxBlurX,
+                               SkBoxBlurProc* boxBlurY,
+                               SkBoxBlurProc* boxBlurXY) {
+    return false;
+}
diff --git a/opts/opts_check_SSE2.cpp b/opts/opts_check_SSE2.cpp
index b40ca9d..efbdbc1 100644
--- a/opts/opts_check_SSE2.cpp
+++ b/opts/opts_check_SSE2.cpp
@@ -12,6 +12,7 @@
 #include "SkBlitRow.h"
 #include "SkBlitRect_opts_SSE2.h"
 #include "SkBlitRow_opts_SSE2.h"
+#include "SkBlurImage_opts_SSE2.h"
 #include "SkUtils_opts_SSE2.h"
 #include "SkUtils.h"
 #include "SkMorphology_opts.h"
@@ -268,6 +269,19 @@
     }
 }
 
+bool SkBoxBlurGetPlatformProcs(SkBoxBlurProc* boxBlurX,
+                               SkBoxBlurProc* boxBlurY,
+                               SkBoxBlurProc* boxBlurXY) {
+#ifdef SK_DISABLE_BLUR_DIVISION_OPTIMIZATION
+    return false;
+#else
+    if (!cachedHasSSE2()) {
+        return false;
+    }
+    return SkBoxBlurGetPlatformProcs_SSE2(boxBlurX, boxBlurY, boxBlurXY);
+#endif
+}
+
 SkBlitRow::ColorRectProc PlatformColorRectProcFactory(); // suppress warning
 
 SkBlitRow::ColorRectProc PlatformColorRectProcFactory() {